#pragma once
#include <iostream>
#include <vector>
#include <semaphore.h>
#include <pthread.h>

const static int defaultcap = 5;

template<class T>
class RingQueue
{
private:
    void P(sem_t &sem)
    {
        sem_wait(&sem);
    }
    void V(sem_t &sem)
    {
        sem_post(&sem);
    }
    void Lock(pthread_mutex_t &mutex)
    {
        pthread_mutex_lock(&mutex);
    }
    void Unlock(pthread_mutex_t &mutex)
    {
        pthread_mutex_unlock(&mutex);
    }
public:
    RingQueue(int cap = defaultcap)
        :ringqueue_(cap),cap_(cap),c_step_(0),p_step_(0)
        {
            sem_init(&cdata_sem_,0,0);
            sem_init(&pspace_sem_,0,cap);

            pthread_mutex_init(&c_mutex_,nullptr);
            pthread_mutex_init(&p_mutex_,nullptr);
        }
    void Push(const T &in)
    {
        P(pspace_sem_);

        Lock(p_mutex_);
        ringqueue_[p_step_]=in;
        p_step_++;
        p_step_%=cap_;
        Unlock(p_mutex_);

        V(cdata_sem_);
    }
    void Pop(T *out)
    {
        P(cdata_sem_);

        Lock(c_mutex_);
        *out=ringqueue_[c_step_];
        c_step_++;
        c_step_%=cap_;
        Unlock(c_mutex_);

        V(pspace_sem_);
    }
    ~RingQueue()
    {
        sem_destroy(&cdata_sem_);
        sem_destroy(&pspace_sem_);

        pthread_mutex_destroy(&c_mutex_);
        pthread_mutex_destroy(&p_mutex_);
    }

private:
    std::vector<T> ringqueue_;
    int cap_;

    int c_step_;
    int p_step_;

    sem_t cdata_sem_;
    sem_t pspace_sem_;

    pthread_mutex_t c_mutex_;
    pthread_mutex_t p_mutex_;
};